The invention relates to a stamping die for hot stamping a material, comprising a profiled stamping surface.
The invention also relates to a method for hot stamping a material using such a stamping die and to a method for producing such a stamping die.
Hot stamping methods are used to form, inscribe, and label various materials, in particular plastics. In doing so, the material is oxidised, formed or pyrolysed.
A device for stamping a film during a thermoforming process is known from DE 10 2004 025 568 A1 and comprises a positive stamping die. The stamping die is heatable in order to achieve flawless stamping without distortion or damage of the film.
DE 38 29 297 A1 discloses a stamping die with metal resistor tracks on a printed circuit board as heating device, on which a profiled die body formed from a rubber mixture is arranged. The arrangement is lined on the underneath with a pressure pad. The design is bulky, wherein the total volume ultimately has to be heated, and additionally can only be used for specific applications due to the soft design.
WO 03/049 915 A1 discloses a heatable hot stamping tool for microstructuring a thermoplastic material in a continuous method. The hot stamping tool is soldered together from segments, wherein the solder has material properties different from the segments. Stamping occurs at a temperature above the glass transition temperature of the plastic to be stamped. At the same time, a pressure is applied, wherein the film to be stamped is cooled under pressure.
Such heatable stamping dies are usually fabricated from metal and are heated externally by means of heating cartridges or gas burners.
A disadvantage of this is that at least the entire stamping die has to be heated, whereby a lot of energy has to be applied accordingly. In addition, in particular in the case of an inscription, clear delimitations of the stamped shapes are desirable. When assembling such a heatable stamping die, the high temperature thereof and the thermal loading of the assembly location must additionally be considered. Skin contact with parts of the stamping die or the regions in the vicinity may lead to burns. The larger the thermal capacity of the heated stamping die, the more time is required before the stamping die will have cooled to such an extent that it can be disassembled or replaced safely. In order to achieve cooling when stamping, the stamping die must either be actively cooled or a sufficient time must elapse before the stamping process is complete.